[0001] The present invention relates to a vehicle body panel arrangement where vehicle body
panels made of aluminum alloy and steel, respectively, are joined by spot welding.
BACKGROUND OF THE INVENTION
[0002] A vehicle body panel arrangement, where three overlapping panels made of aluminium
are joined by spot welding is known from
DE 100 48 233 A1.
[0003] There is a growing demand to use body panels made of various aluminum alloys to minimize
the weight of the vehicle body. However, because body panels made of aluminum alloy
may not be able to provide an adequate vehicle body strength by themselves, it has
been proposed to use steel panels for major frame components and selectively use body
panels made of aluminum alloy only in parts such as a roof outer panel that do not
require a high mechanical strength and have large surface areas.
[0004] Galvannealed steel sheet is also a preferred material for vehicle body outer panels
because of its high corrosion resistance and its capability to wear a highly smooth
paint coating, but is known to form a relatively poor bonding when spot welded to
aluminum sheet.
[0005] As a technology for ensuring a high welding strength between sheets made of two different
metallic materials such as aluminum and steel materials, it is known to interpose
a clad metal sheet consisting of two layers of aluminum and steel materials that are
firmly joined together by rolling or the like between the sheets made of different
materials that are desired to be joined together as proposed in
Japanese patent No. 3355790. This ensures a high spot welding strength, but has the disadvantage to require the
clad metal sheet as an additional component that adds to the cost.
[0006] Another problem when joining sheet metal components is galvanic corrosion which is
caused when electrolyte such as rain water seeps into a gap between members made of
different metallic materials.
Japanese patent laid open publication No. 2000-272541 proposes a method for preventing galvanic corrosion in a vehicle body. In this method,
non-through type rivets are used for joining two panel members, and a sealant is applied
to parts remote from the rivets. However, the use of rivets requires a special piece
of equipment which is otherwise unnecessary, and this adds to the manufacturing cost.
[0007] From
US 2,878,552, there is known a three-layered armature of a relay, in which the middle layer has
apertures and the two outer layers are welded to each other via these apertures.
BRIEF SUMMARY OF THE INVENTION
[0008] In view of such problems of the prior art, a primary object of the present invention
is to provide a vehicle body panel arrangement made of different sheet metal materials
including those that cannot be favorably welded to each other without increasing the
number of component parts.
[0009] A second object of the present invention is to provide a vehicle body panel welding
arrangement, where a vehicle body panel made of aluminum is joined with another vehicle
body panel made of steel sheet in a highly secure manner.
[0010] A third object of the present invention is to provide a vehicle body arrangement,
where a vehicle body panel made of aluminum is joined with another vehicle body panel
made of galvannealed steel sheet by spot welding.
[0011] A fourth object of the present invention is to provide a vehicle body panel arrangement,
where vehicle body panels made of different metallic materials are joined by spot
welding without incurring the problem of galvanic corrosion.
[0012] According to the present invention, at least a part of such objects can be accomplished
by providing a vehicle body panel arrangement according to claim 1. An embodiment
according to the present invention comprises inter alia a first vehicle body member
including a first outer panel made of a first sheet metal material that is joined
with a second vehicle body member including a second outer panel made of a second
sheet metal material that cannot be favorably welded to the first outer panel and
an inner panel made of a third sheet metal material that can be favorably welded to
the first outer panel and at least partly overlapping with the second outer panel,
wherein: the overlapping part of the second outer panel is provided with a notch exposing
a part of the inner panel, and the first outer panel is welded, for instance spot
welded to the exposed part of the inner panel. The first sheet metal material consists
of aluminum or aluminum alloy, and the second sheet metal consists of galvannealed
steel sheet which has favorable properties for use in vehicle body components but
is not suitable for welding with aluminum sheet. The third sheet metal consists of
non-galvannealed steel sheet which may be hot-dip galvanized steel sheet, electrogalvanized
steel sheet or simple non-galvanized steel sheet.
[0013] Thereby, the first vehicle body member can be joined to the second vehicle body member
by welding the first outer panel to the inner panel which can be favorably welded
to the first outer panel, instead of the second outer panel which cannot be favorably
welded to the first outer panel. The second outer panel and inner panel may be joined
by welding or other means before joining the first vehicle body member and second
vehicle body member with each other. Also, this arrangement can be implemented by
using existing facilities for assembling vehicle body members without requiring any
additional manufacturing facility.
[0014] According to a preferred embodiment of the present invention, the inner panel comprises
two layers of sheet metal (a stiffener and an inner panel), and the layer adjacent
to the second outer panel (the stiffener) consists of non-galvannealed steel sheet.
The exposed part of the inner panel may be provided with a projection. The projection
may be, for instance, rectangular in shape, and substantially complementary to the
notch in shape, and may have a height corresponding to a thickness of the second outer
panel.
[0015] The present invention also provides a favorable sealing arrangement in which an upper
part of the projection is welded to the first outer panel, and a part of the inner
panel surrounding the projection defines a recess in cooperation with a peripheral
edge of the notch that receives a sealant therein. Typically, the second outer panel
is provided with a plurality of notches along an edge thereof, and the sealant is
applied as a strip that extends along and over an inner peripheral line of the notches
in parallel with the edge of the second outer panel.
[0016] In particular, if the exposed part of the inner panel is provided with a projection
having a height slightly greater than a thickness of the second outer panel, the second
outer panel may be electrically insulated from the first outer panel via a layer of
the sealant so that galvanic corrosion in this part can be favorably avoided.
[0017] According to an alternate embodiment of the present invention, the second outer panel
comprises two layers of sheet metal (an outer panel and a stiffener), and the inner
panel consists of non-galvannealed steel sheet so that the first outer panel may be
welded to the inner panel through a notch formed in the second outer panel across
the two layers.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] Now the present invention is described in the following with reference to the appended
drawings, in which:
Figure 1 is a simplified perspective view of a vehicle body to which the present invention
is applied;
Figure 2 is a sectional view taken along line II-II of Figure 1;
Figure 3 is a fragmentary perspective view showing the welding arrangement embodying
the present invention;
Figure 4a is a simplified sectional view showing the process of welding together three
panel members to form a roof side rail;
Figure 4b is a simplified sectional view showing the process of welding a roof outer
panel to the roof side rail;
Figure 5 is a sectional view showing the joint between the roof outer panel to the
roof side rail;
Figure 6 is a view similar to Figure 5 showing a modified embodiment of the present
invention;
Figure 7 is a view similar to Figure 3 showing a second embodiment of the present
invention;
Figure 8a is a view similar to Figure 4a showing the second embodiment of the present
invention;
Figure 8b is a view similar to Figure 4b showing the second embodiment of the present
invention;
Figure 9 is a plan view showing the sealant deposited on the roof side rail in the
second embodiment of the present invention; and
Figure 10 is a vertical sectional view showing the process of joining the roof outer
panel to the roof side rail in the second embodiment of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0019] Figure 1 shows an automotive vehicle body embodying the present invention. The vehicle
body 1 comprises a roof outer panel 2 made of 6,000 series aluminum alloy, for instance,
and a pair of roof side rails 3 each consisting of a plurality of sheet metal components
and joined to a corresponding side edge of the roof outer panel 2.
[0020] As shown in Figure 2, each roof side rail 3 consists of an outer panel 4, a stiffener
5 and an inner panel 6. These components are provided with lateral flanges 4a, 5a
and 6a on each lateral side that are overlaid one another, and are jointly spot welded
at the lateral flanges on each side. One of the side edges of the roof side rail 3
is welded to a corresponding lateral flange 2a of the roof outer panel 2 thereby forming
a vehicle roof.
[0021] In this roof side rail 3, the outer panel 4 is made of galvannealed steel sheet while
the stiffener 5 and inner panel 6 are made of hot-dip galvanized or electrogalvanized
steel sheet (if desired, may also be made of simple non-galvanized steel sheet). In
particular, the inner panel 6 which does not directly contact the flange portion 2a
of the roof outer panel 2 may consist of non-galvanized steel sheet.
[0022] As shown in Figure 3, the flange portion 4a of the outer panel 4 of the roof side
rail 3 is provided with a plurality of rectangular notches 11 at a regular interval
along the outer edge thereof. The flange portions 5a and 6a of the stiffener 5 and
inner panel 6 are provided with upward projections 12 that fit into the rectangular
notches 11 of the flange portion 4a of the outer panel 4. The height of these upward
projections 12 is substantially equal to the thickness of the outer panel 4.
[0023] The process of spot welding the roof outer panel 2 to the roof side rail 3 is now
described in the following. First of all, the flange 5a of the stiffener 5 is placed
on the corresponding flange 6a of the inner panel 6, and the flange 4a of the outer
panel 4 is placed on the flange 5a of the stiffener 5 with the projections 12 aligned
with the notches 11. A pair of electrode tips 13 of a spot welder are applied to the
outer surfaces of the flanges 4a and 6a of the outer panel 4 and inner panel 6, respectively,
and the three flanges 4a, 5a and 6a are welded together as illustrated in Figure 4a.
More specifically, the upper electrode tip 13 is applied to a part of the flange 4a
of the outer panel 4 which does not correspond to any of the notches 11.
[0024] Then, the flange 2a of the roof outer panel 2 is placed on the flange 4a of the outer
panel 4 of the roof side rail 3, and the electrode tips 13 of the spot welder are
applied to the outer surfaces of the flanges 6a and 2a of the inner panel 6 and roof
outer panel 2, respectively, and the three flanges 2a, 5a and 6a are welded together
as illustrated in Figure 4b. In particular, the upper electrode tip 13 is applied
the part of the flange 2a of the roof outer panel 2 that corresponds to the notches
11 of the outer panel 4 or the part that corresponds to the projections 12 of the
roof side rail 3. Thereby, the flange 2a of the roof outer panel 2 is welded to the
upper surface of each projection 12 that is exposed by the corresponding notch 11.
Thereby, the roof side rail 3 is completed as illustrated in Figure 5.
[0025] In this case, the roof outer panel 2 is welded to the stiffener 5 which is made of
hot-dip galvanized or electrogalvanized steel sheet. The ductility ratio (peel strength
/shear strength) of a weld between a 6,000 series aluminum alloy sheet and a non-galvannealed
steel sheet (hot-dip galvanized or electrogalvanized steel sheet) is about 0.35, and
this is significantly greater than the ductility ratio of a weld between a pair of
steel sheets which is about 0.30. Therefore, a weld of an adequate mechanical strength
can be achieved according to the present invention as compared to the case where a
weld is formed between the roof outer panel 2 made of 6,000 series aluminum alloy
and the outer panel 4 made of galvannealed steel sheet. Therefore, the present invention
eliminates the need for additional structural members, and contributes to the reduction
in the number of component parts.
[0026] In the foregoing embodiment, the aligning of the outer panel 4, stiffener 5 and inner
panel 6 is simplified by the positioning action of the notches 11 and projections
12, and this facilitates the manufacturing process of the roof side rail 3. In particular,
if the height of each projection 12 is selected to be substantially similar to the
plate thickness of the roof side rail outer panel 4, because the flange surface of
the roof side rail 3 onto which the flange 2a of the roof outer panel abuts may consist
of a substantially flat surface, the bottom surface of the groove formed jointly by
the flange 2a of the roof outer panel 2 and the roof side rail outer panel 4 can be
made substantially flat, and this prevents water from being trapped on the bottom
surface of the groove. Also, by selecting the height of each projection 12 to be substantially
similar to the plate thickness of the roof side rail outer panel 4, the gap between
the inner peripheral edge of each notch 11 and the outer periphery of the corresponding
projection 12 may be used as a reservoir for a sealant.
[0027] Figure 6 shows a modified embodiment, in which the notches 11 are provided not only
in the flange 4a of the outer panel 4 but also in the flange 5a of the stiffener a
at positions corresponding to those of the outer panel 4. The projections 11 are formed
only in the flange 6a of the inner panel 6, and have a height corresponding to the
combined thickness of the outer panel 4 and stiffener 5. In this case, the flanges
4a, 5a and 6a of the roof side rail panels 4, 5 and 6 are spot welded in the parts
where the notches 11 are absent, and the thus formed roof side rail 3 is welded to
the roof outer panel 2 by welding the edge 2a of the roof outer panel 2 to the exposed
parts of the flange 6a of the inner panel 6a. In this case, the roof outer panel 12
is made of aluminum or aluminum alloy, and the inner panel 6 is made of non-galvannealed
steel sheet which can be favorably welded to the roof outer panel 2 made of aluminum
material while the outer panel 4 (if desired, the stiffener 5 also) may be made of
galvannealed steel sheet.
[0028] Figure 7 shows a second embodiment of the present invention. In this roof side rail
3, the outer panel 4 is made of galvannealed steel sheet while the stiffener 5 and
inner panel 6 are made of hot-dip galvanized or electrogalvanized steel sheet. In
this case also, the stiffener 5 and inner panel 6, in particular the inner panel 6
which does not directly contact the flange portion 2a of the roof outer panel 2, may
also consist of simple non-galvanized steel sheet.
[0029] As shown in Figure 7, the flange portion 4a on the roof panel side of the outer panel
4 of the roof side rail 3 is provided with a plurality of rectangular notches 11 at
a regular interval along the outer edge thereof. The corresponding flange portions
5a and 6a of the stiffener 5 and inner panel 6 are provided with upward projections
22 that fit into the rectangular notches 11 of the flange portion 4a of the outer
panel 4. In this case, each projection 22 consists of a part-spherical projection
which is circular in shape as seen in plan view. The height of these upward projections
22 is slightly greater than the thickness of the outer panel 4.
[0030] The process of spot welding the roof outer panel 2 to the roof side rail 3 is now
described in the following. First of all, the flange 5a of the stiffener 5 is placed
on the corresponding flange 6a of the inner panel 6, and the flange 4a of the outer
panel 4 is placed on the flange 5a of the stiffener 5 with the projections 22 aligned
with the notches 11. A pair of electrode tips 13 of a spot welder are applied to the
outer surfaces of the flanges 4a and 6a of the outer panel 4 and inner panel 6, respectively,
and the three flanges 4a, 5a and 6a are welded together as illustrated in Figure 8a.
More specifically, the upper electrode tip 13 is applied to the part of the flange
4a of a part of the outer panel 4 which does not correspond to the notch 11.
[0031] Then, as shown in Figure 9, a sealant 14 is applied to the upper surface of the flange
4a of the outer panel 4 as a strip that continuously extends along and over the inner
edges of the notches 11. Therefore, as best shown in Figure 10, the sealant 14 is
present not only in the recess defined in each notch between the inner edge of the
notch 11 and the opposing wall of the projection 22 but also on the part of the upper
surface of the flange 4a of the outer panel 4 immediately inward of the inner edges
of the notches 11.
[0032] When the flange 2a of the roof outer panel 2 is placed on the flange 4a of the outer
panel 4 of the roof side rail 3, the sealant 14 is interposed between the lower surface
of the flange 2a of the roof outer panel 2 and the upper surface of the flange 4a
of the outer panel 4 as film on the one hand and is filled into the recess defined
in each notch 11 on the other hand.
[0033] Thereafter, the electrode tips 13 of the spot welder are applied to the outer surfaces
of the flanges 6a and 2a of the inner panel 6 and roof outer panel 2, respectively,
and the three flanges 2a, 5a and 6a are welded together as illustrated in Figure 8b.
In particular, the upper electrode tip 13 is applied the part of the flange 2a of
the roof outer panel 2 that corresponds to any of the notches 11 of the outer panel
4 or the part that corresponds to any of the projections 12 of the roof side rail
3. Thereby, the flange 2a of the roof outer panel 2 is welded to the upper surface
of each projection 22 that is exposed by the corresponding notch 11. Thereby, the
roof side rail 3 is completed.
[0034] In this case also, the substantially same welding strength similar to that of the
first embodiment was achieved. Furthermore, the sealant 14 continuously extends as
a strip along and over the inner edges of the notches 11. In particular, the sealant
14 is interposed between the flanges 2a and 4a of the roof outer panel 2 and outer
panel 4, and is filled into the recess in the notches 11 in the region covered by
this strip. Thereby, the electric contact between the roof outer panel 2 and outer
panel 4 is avoided so that galvanic corrosion is minimized. The sealant 14 that is
filled into the recesses in the notches 11 prevents intrusion of moisture into the
gap between the roof outer panel 2 and outer panel 4.
[0035] The shape of each projection 12 is not limited to the rectangular shape and circular
shape used in the foregoing embodiments, but may also be polygonal, elliptic or the
like as long as it is suitable for the electrode tip 13 of a welder to adequately
press upon. The shape of each notch 11 is also not limited to the rectangular shape
used in the foregoing embodiments, but may be rounded or otherwise deviate from the
rectangular shape as long as it does not interfere with the projection 12.
[0036] In the illustrated embodiments, the projections 12, 22 were formed on the side of
the roof side rail 3, but, if desired, may also be formed on the side of the roof
outer panel 2 while the flanges 5a and 6a of the stiffener 5 and inner panel 6 are
(or the flange 6a of the inner panel 6) substantially flat.
[0037] Although the present invention has been described in terms of preferred embodiments
thereof, it is obvious to a person skilled in the art that various alterations and
modifications are possible without departing from the scope of the present invention
which is set forth in the appended claims.
1. A vehicle body panel arrangement including a first outer panel (2) made of aluminum
or aluminum alloy sheet, a second outer panel (4) made of galvannealed steel sheet,
and an inner panel (5, 6) made of non-galvannealed steel sheet, the three panels being
at least partly overlapping with one another, in that order, wherein:
in the overlapping part of the three panels the second outer panel (4) is provided
with a notch (11) exposing a part of the inner panel (5, 6), and the second outer
panel (4) is spot-welded to the inner panel (5, 6) while the first outer panel (2)
is spot-welded to the exposed part of the inner panel (5, 6).
2. The vehicle body panel arrangement according to claim 1, wherein the exposed part
of the inner panel (5, 6) is provided with a projection (12) having a height corresponding
to a thickness of the second outer panel (4).
3. The vehicle body panel arrangement according to claim 1, wherein the inner panel (5,
6) comprises two layers of sheet metal.
4. The vehicle body panel arrangement according to claim 2, wherein the projection (12)
is substantially complementary to the notch (11) in shape.
5. The vehicle body panel arrangement according to claim 1, wherein the exposed part
of the inner panel (5, 6) is provided with a projection (22), and an upper part of
the projection (22) is welded to the first outer panel (2), a part of the inner panel
(5, 6) surrounding the projection defining a recess in cooperation with a peripheral
edge of the notch (11) that receives a sealant (14) therein.
6. The vehicle body panel arrangement according to claim 5, wherein the second outer
panel (4) is provided with a plurality of notches along an edge thereof, and the sealant
(14) is applied as a strip that extends along and over an inner peripheral line of
the notches in parallel with the edge of the second outer panel.
7. The vehicle body panel arrangement according to claim 6, wherein the projection (22)
has a height slightly greater than a thickness of the second outer panel (4).
8. The vehicle body panel arrangement according to claim 1, wherein the second outer
panel comprises two layers of sheet metal (Figure 6: 4, 5).
1. Fahrzeugaufbauplatten-Anordnung, enthaltend eine erste Außenplatte (2), die aus Aluminium-
oder Aluminiumlegierungsblech hergestellt ist, eine zweite Außenplatte (4), die aus
Galvaneeled-Stahlblech hergestellt ist, und eine Innenplatte (5, 6), die aus Nicht-Galvaneeled-Stahlblech
hergestellt ist, wobei diese drei Platten in dieser Reihenfolge einander zumindest
teilweise überlappen, worin:
in dem Überlappungsteil der drei Platten die zweite Außenplatte (4) mit einer Ausnehmung
(11) versehen ist, die ein Teil der Innenplatte (5, 6) frei lässt, und die zweite
Außenplatte (4) an die Innenplatte (5, 6) punktgeschweißt ist, während die erste Außenplatte
(2) an das frei gelassene Teil der Innenplatte (5, 6) punktgeschweißt ist.
2. Fahrzeugaufbauplatten-Anordnung nach Anspruch 1, worin das frei gelassene Teil der
Innenplatte (5, 6) mit einem Vorsprung (12) versehen ist, dessen Höhe einer Dicke
der zweiten Außenplatte (4) entspricht.
3. Fahrzeugaufbauplatten-Anordnung nach Anspruch 1, worin die Innenplatte (5, 6) zwei
Metallblechschichten aufweist.
4. Fahrzeugaufbauplatten-Anordnung nach Anspruch 2, worin der Vorsprung (12) mit der
Ausnehmung (11) im Wesentlichen form komplementär ist.
5. Fahrzeugaufbauplatten-Anordnung nach Anspruch 1, worin das frei gelassene Teil der
Innenplatte (5, 6) mit einem Vorsprung (22) versehen ist, und ein oberer Teil des
Vorsprungs (22) an die erste Außenplatte (2) geschweißt ist, wobei ein den Vorsprung
umgebendes Teil der Innenplatte (5, 6) im Zusammenwirken mit einem Umfangsrand der
Ausnehmung (11) eine Vertiefung definiert, die darin ein Dichtmittel (14) aufnimmt.
6. Fahrzeugaufbauplatten-Anordnung nach Anspruch 5, worin die zweite Außenplatte (4)
entlang ihrem Rand mit einer Mehrzahl von Ausnehmungen versehen ist, und das Dichtmittel
(14) als Streifen aufgetragen ist, der sich entlang und über eine Innenumfangslinie
der Ausnehmungen parallel zum Rand der zweiten Außenplatte erstreckt.
7. Fahrzeugaufbauplatten-Anordnung nach Anspruch 6, worin der Vorsprung (22) eine Höhe
hat, die etwas größer ist als die Dicke der zweiten Außenplatte (4).
8. Fahrzeugaufbauplatten-Anordnung nach Anspruch 1, worin die zweite Außenplatte zwei
Metallblechschichten aufweist (Figur 6: 4,5).
1. Agencement pour panneaux de carrosserie de véhicule comprenant un premier panneau
extérieur (2), réalisé en tôle d'aluminium ou d'alliage d'aluminium, un deuxième panneau
extérieur (4), réalisé en tôle d'acier recuite après galvanisation, et un panneau
intérieur (5, 6), réalisé en tôle d'acier non recuite après galvanisation, les trois
panneaux étant en chevauchement au moins partiel les uns par rapport aux autres, dans
cet ordre, dans lequel :
dans la partie en chevauchement des trois panneaux, le deuxième panneau extérieur
(4) est pourvu d'une encoche (11), exposant une partie du panneau intérieur (5, 6),
et le deuxième panneau extérieur (4) est soudé par points au panneau intérieur (5,
6), tandis que le premier panneau extérieur (2) est soudé par points à la partie exposée
du panneau intérieur (5, 6).
2. Agencement pour panneaux de carrosserie de véhicule selon la revendication 1, dans
lequel la partie exposée du panneau intérieur (5, 6) est pourvue d'une saillie (12)
ayant une hauteur correspondant à une épaisseur du deuxième panneau extérieur (4).
3. Agencement pour panneaux de carrosserie de véhicule selon la revendication 1, dans
lequel le panneau intérieur (5, 6) comprend deux couches de tôle métallique.
4. Agencement pour panneaux de carrosserie de véhicule selon la revendication 2, dans
lequel la saillie (12) est d'une forme sensiblement complémentaire à l'encoche (11).
5. Agencement pour panneaux de carrosserie de véhicule selon la revendication 1, dans
lequel la partie exposée du panneau intérieur (5, 6) est pourvue d'une saillie (22),
et une partie supérieure dé la saillie (22) est soudée au premier panneau extérieur
(2), une partie du panneau intérieur (5, 6) entourant la saillie définissant une cavité,
en coopération avec un bord périphérique de l'encoche (11) qui reçoit à l'intérieur
un produit d'étanchéité (14).
6. Agencement pour panneaux de carrosserie de véhicule selon la revendication 5, dans
lequel le deuxième panneau extérieur (4), est muni d'une pluralité d'encoches le long
d'un de ses bords, et le produit d'étanchéité (14) est appliqué sous forme d'une bande
s'étendant le long et sur une ligne périphérique intérieure des encoches, parallèlement
au bord du deuxième panneau extérieur.
7. Agencement pour panneaux de carrosserie de véhicule selon la revendication 6, dans
lequel la saillie (22) présente une hauteur légèrement plus grande qu'une épaisseur
du deuxième panneau extérieur (4).
8. Agencement pour panneaux de carrosserie de véhicule selon la revendication 1, dans
lequel le deuxième panneau extérieur comprend deux couches de tôle métallique (Figure
6; 4, 5).